Flat panel liquid crystal displays (LCDs) are popular display devices for conveying information generated by a computer system. The decreased weight and size of a flat panel display greatly increases its versatility over a cathode ray tube (CRT) display. Flat panel LCD monitors are used today in many applications including the computer component and computer periphery industries where flat panel LCD monitors are an excellent display choice for lap-top computers and other portable electronic devices. Because flat panel LCD technology is improving, more and more flat panel LCD monitors are rapidly replacing CRT displays in other mainstream applications, such as desktop computers, high-end graphics computers, and as televisions and other multi-media monitors.
In flat panel LCD monitors, much like conventional CRT displays, a white pixel is composed of a red, a green and a blue color point or “spot”. When each color point of the pixel is excited simultaneously and with the appropriate energy, white can be perceived by the viewer at the pixel screen position. To produce different colors at the pixel, the intensity to which the red, green and blue points are driven is altered in well known fashions. The separate red, green and blue data that corresponds to the color intensities of a particular pixel is called the pixel's color data. Color data is often called gray scale data. The degree to which different colors can be achieved within a pixel is referred to as gray scale resolution. Gray scale resolution is directly related to the amount of different intensities, or shades, to which each red, green and blue point can be driven.
The method of altering the relative color intensities of the color points across a display screen is called white balance adjustment (also referred to as color balance adjustment, color temperature adjustment, white adjustment, or color balancing). In a display, the “color temperature” of white correlates to the relative percentage contributions of its red, green and blue intensity components. In addition, the “color temperature” of white correlates to the luminous energy given off by an ideal black body radiating sphere at a particular temperature expressed in degree Kelvin (K). Relatively high degree K color temperatures represent “white” having a larger blue contribution (e.g., a “cooler” look). Relatively small degrees K color temperatures represent “white” having a larger red contribution (e.g., a “warmer” look). Generally, the color temperature of a display screen is adjusted from blue to red while avoiding any yellow-ish or green-ish variations within the CIE chromaticity diagram.
In conventional CRT devices, white balance is adjusted by independently altering the voltage gains of the primary electron guns (e.g., red, green and blue guns) depending on the desired color temperature. However, this prior art color balancing technique reduces the dynamic gray scale range of some or all of the RGB colors, as well as the overall color gamut of the display. In some conventional flat panel LCDs, a shift in color temperature may be achieved by adjusting the relative intensities of the RGB gray levels in a manner analogous to the adjusting of the gain of the electron guns of the CRT devices. However, this prior art method also causes the LCDs to lose dynamic gray scale range and color gamut.
Another prior art method of adjusting the white balance within a flat panel LCD screen pertains to altering the physical color filters used to generate the red, green and blue color points. By altering the color of the filters, the color temperature of the LCD screen can be adjusted. However, this adjustment is not dynamic because the color filters need to be physically (e.g., manually) replaced each time adjustment is required. It would be advantageous to provide a color balancing mechanism for a flat panel LCD screen that can respond, dynamically, to required changes in the color temperature of the display.
The white balance adjustment for a display is important because many users want the ability to alter the display's color temperature for a variety of different reasons. For instance, the color temperature might be varied based on a viewer's personal taste. In other situations, color temperature adjustment may be needed to compensate for manufacturing variations in the display. In some situations, color temperature adjustment can correct for the effects of aging in some displays. Particularly, color critical applications such as pre-press soft proofing, desktop publishing, graphics design, medical imaging, and digital photography and video editing, etc., require white balance values and gamma values of different displays to be precisely matched in order to accurately view and exchange images with confidence. Thus, without an efficient and effective method of providing dynamic white balance adjustment capabilities, flat panel LCDs have heretofore been unused in color critical applications which require precise color calibration and matching. Therefore, what is needed is an efficient and effective method of providing dynamic white balance adjustment capabilities in flat panel LCDs.
Accordingly, the present invention provides a display for mechanism and method for dynamically adjusting the color balance of a flat panel liquid crystal display without compromising the gray-scale resolution of the pixels. Further, the present invention provides a mechanism and method for adjusting the color balance of a flat panel display screen without complicated circuitry. Embodiments of the present solution also performs gamma correction and frame rate time domain modulation to reduce scalloping and visual artifacts. These and other advantages of the present invention not specifically mentioned above will become clear within discussions of the present invention presented herein.